Manchester United Supporters' Trust have threatened to take legal action against Hammersmith and Fulham Council over the reduction of tickets made available for the game at Chelsea.
United's trip to Stamford Bridge has been rescheduled to Saturday 22 October because of the Blues' Champions League commitments, but their ticket allowance has been cut to just 2,370 from 2,994 because of concerns over policing.
"We write to request you urgently issue a fresh safety certificate for the above fixture with allowance for the full ticket allocation of 3,000 MUFC fans," a solicitors’ letter to Hammersmith and Fulham Council began.
"The decision is challenged on the basis that there is no rational reason to reduce the ticket allocation for away fans at a 5.30pm kick-off when it is accepted that there would be a full ticket allocation at a fixture beginning no later than 4.45pm.
"If we do not receive a reply to this letter from you by the above deadline for response, or if you confirm that you refuse to reverse your decision, then we reserve the right to commence judicial review proceedings against you without further notice."